The present disclosure pertains to material separators, and in particular to rock/soil separators for use during excavation.
Material separators for separating rocks from finer material, also known as “grizzly” separators, allow an operator of a loader (e.g., an excavator, backhoe, front end loader, etc.) to dump a bucket load of excavated material on an inclined screening surface to screen rocks, rubble, debris and other large material from soil that, once screened, can be used, e.g., as backfill or landscape topsoil. The screening surface is mounted at an incline on a supporting frame, and is generally comprised of a number of parallel bars, the lengths of which extend generally in the direction of the incline.
An example of such a separator is described in U.S. 2010/0059416, the full disclosure of which is incorporated herein by reference. In the separator described in U.S. 2010/0059416 some of the bars are attached to the supporting frame (fixed bars), while alternating bars are movable relative to the frame (shift bars.) The shift bars are mounted such that they can pivot about their upper ends, allowing the lower ends to be lifted away from the supporting frame to free trapped rocks and other large material from the screening surface. Lifting may be accomplished, for example, by placing the bucket of a loader under an actuator, e.g., a lift bar to which the shift bars are bolted, and pushing upward. The lift bar is generally located relatively close to the lower ends of the shift bars, so as to maximize the lever arm about the pivot point.
In some cases, the spacing between the bars is adjustable. However, this generally requires unbolting each of the bars from the lift bar, or undoing fasteners that attach the bars to the frame.